Apostate prophet wont find his salt; Quran says salt and sweet water dont mix?

In answer to the video "43 Scientific Mistakes in the Quran"

Those to whom the verse was primarily addressed, the Arabs, were land and sea travellers. They passed through estuaries and points where a river met the ocean to see both bodies of water mixing. The Arabic "bahr" means a vast water expanse, be it the ocean, a big river or lake. None of the verses 25:53,27:61,55:19 say that a barrier prevents them from mixing. In fact it clearly says that they meet and mix/maraja 55:19. 

The verse immediately follows by saying that despite this mixing, there is an unbreakable barrier between the 2 water types referred to earlier. And it is the phenomenon that sustains life on this earth by keeping the water types perpetually appart, salt and sweet, despite their perpetual mixing when they meet. The verse comes in the context of providing evidence of God's bounties, the primary example being exactly this, the constant phenomenon of having 2 distinct water types available, despite their continuous flow and mixing into one another. Had this phenomenon of evaporation and filtration of salt not existed, life as we know it would have been impossible 

55:21"Which then of the bounties of your Sustainer will you deny?"  

A river meeting the ocean without mixing is not a bounty from God and is irrelevant in stimulating the gratefulness of the reader and audience, which is the whole point of the passage. Another spiritual parallel the verses make with that phenomenon is the existence of 2 types of humans, the spiritually aware and the rest. In this world they mix and mingle on a physical level but will remain separate on the metaphysical sphere. But the Merciful has placed in everyone the potential to thrive spiritually, even the sinner, if he chooses to repent. And so, the verse also states that pearls can be harvested from fresh and saltwater, just as there is spirituality in the righteous as well as the sinner. The imagery is beautiful and uplifting, as opposed to the NT's exclusivist and racist notion of "avoid sharing your pearls with pigs" Matt7. Corals, as a side note, live and grow in seawater but may be found in rivers, such as the massive reef of the Amazon. Corals can also thrive in estuaries, where the 2 bodies of water meet.

Talking about everlasting, unbreakable barrier, the Hebrew Bible in Jer5:22 speaks of the sea as unable to permanently invade and inundate dry land, forcibly kept till the end of times behind the shore, thus also showing ignorance of the phenomenon of tides

"I made sand a boundary for the sea, an everlasting ordinance, which it cannot pass, and [its waves] toss themselves, yet they cannot prevail; and its waves roar, but they do not pass it."